In earlier work [1] we looked at how often dynamic features
are used across a corpus of 19 popular open-source PHP
systems. However, this work did not explore trends over time
in the use of these features. These trends can be important
for making reasonable assumptions about the code to be
analyzed and for deciding where work on providing more
precise approximations of runtime behavior will have the
greatest impact. In this paper, we start by focusing on two of the
systems from our original corpus, WordPress and MediaWiki,
exploring how uses of variable features, magic methods, and
eval have changed over time. Our initial results show that
the use of some variable features, such as variable properties,
is increasing, meaning these features will show up more often
in analyzed code, while the use of others is decreasing or
holding steady; magic methods are now more common, but are
still (in an absolute sense) uncommon; and uses of eval are
fortunately rare and becoming rarer.